Optical absorption of zigzag carbon nanotubes at finite temperature

We investigate the rate of optical absorption of carbon nanotubes and graphene plane using full dispersion. Tight binding model Hamiltonian is used to calculate conductivity and optical absorption of the system. The contribution of both interband and intraband transitions on the optical spectra is considered. Our results are valid up to the ultraviolet region. The results for monolayer graphene sheet show a peak in energy E≈2eV. Furthermore, we investigate the effect of temperature and carbon nanotube radius on the optical spectra. Our results show that the peaks of optical conductivity shift to lower photon energy due to increase of the diameter of zigzag carbon nanotubes.

► The theoretical calculation of optical absorption of carbon nanotubes and graphene by Green's function approach.
► The investigation of behavior of optical spectrum versus radius of carbon nanotube.
► The investigation of behavior of optical spectrum versus temperature.